The unique two-dimensional structure of graphene leads to the fact that the electrons pass through it in a different way than it does with most other materials. One of the consequences of this transfer is the inability to stop the electrons by applying voltage. And this is a problem because when using graphene to create, for example, quantum computers, it is necessary to be able to stop and control these unique electrons. An international team of scientists has solved a long-standing problem. The research is published in the journal Advanced Materials.
The experimental team used atomic bricks to build walls capable of stopping graphene electrons. Atomic walls bounding electrons led to the formation of structures. Then their spectrum was compared with theoretical predictions, thereby demonstrating that the electrons were limited. In particular, scientists were able to achieve engineered structures that led to an almost perfect electron confinement. This is evidenced by the appearance of sharp resonances of quantum wells with a surprisingly long lifetime.
The study clearly shows that impermeable walls for graphene electrons can be created by collective manipulation of a large number of hydrogen atoms. In the experiments, a scanning tunneling microscope was used to create artificial walls with subnanometric accuracy. This led to the appearance of graphene nanostructures of an arbitrarily complex shape with sizes from two nanometers to one micron.
It is important to note that this method is non-destructive, which allows researchers to erase and restore nanostructures as they wish. This provides an unprecedented level of control to create artificial graphene devices.
Experiments show that engineered nanostructures are capable of perfectly retaining graphene electrons in these artificially created models. In doing so, they overcome the critical problem created by Klein tunneling. Ultimately, this opens up many new interesting possibilities – nanostructures realize quantum dots of graphene, which can be selectively coupled, thereby opening up the possibility for scientists to create artificial quantum matter.